In vitro and in vivo models will be studied to elucidate the mechanisms responsible for the interaction of oncogenic virus, thymic epithelial cells and thymic cortical cells which result in lymphoma development in the AKR mouse. Cell culture methods to induce transformation of mouse thymic cells to lymphoma cells will be developed. Studies will utilize diffusion chambers to isolate cellular components to determine the role of thymic humoral factors in lymphomagenesis.